calling unmanaged c++ dll from c# in .NET 4.0 VS 2010

Hi I want t o learn how to pass parameters between a VS 2010 c# application and an unmanaged c++ dll. So I would like someobody to develop me a VS 2010 solution with 2 projects The first project is an unmanaged c++ dll that will have functions to take the following parameter types and return a string value for the parameter Function Parameter GetDateStr single date parameter GetDblStr single double parameter GetStrStr single string parameter (does nothing really) GetDateArrayStr single date array parameter, returns a string which is the , delimited list of dates GetDblArrayStr single array of doubles, returns a string which is a , delimited string of doubles The second project should be a simple c# .net 4.0 application that calls the dll functions , the data can be hard coded in the application or input by the user. As I say this is just to help me understand how to call c++ dlls from c# Steve